super.c

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/*
 *  linux/fs/hfs/super.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * (C) 2003 Ardis Technologies <[email protected]>
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * This file contains hfs_read_super(), some of the super_ops and
 * init_hfs_fs() and exit_hfs_fs().  The remaining super_ops are in
 * inode.c since they deal with inodes.
 *
 * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/nls.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/vfs.h>

#include "hfs_fs.h"
#include "btree.h"

static struct kmem_cache *hfs_inode_cachep;

MODULE_LICENSE("GPL");

static int hfs_sync_fs(struct super_block *sb, int wait)
{
    hfs_mdb_commit(sb);
    return 0;
}

/*
 * hfs_put_super()
 *
 * This is the put_super() entry in the super_operations structure for
 * HFS filesystems.  The purpose is to release the resources
 * associated with the superblock sb.
 */
static void hfs_put_super(struct super_block *sb)
{
    cancel_delayed_work_sync(&HFS_SB(sb)->mdb_work);
    hfs_mdb_close(sb);
    /* release the MDB's resources */
    hfs_mdb_put(sb);
}

static void flush_mdb(struct work_struct *work)
{
    struct hfs_sb_info *sbi;
    struct super_block *sb;

    sbi = container_of(work, struct hfs_sb_info, mdb_work.work);
    sb = sbi->sb;

    spin_lock(&sbi->work_lock);
    sbi->work_queued = 0;
    spin_unlock(&sbi->work_lock);

    hfs_mdb_commit(sb);
}

void hfs_mark_mdb_dirty(struct super_block *sb)
{
    struct hfs_sb_info *sbi = HFS_SB(sb);
    unsigned long delay;

    if (sb->s_flags & MS_RDONLY)
        return;

    spin_lock(&sbi->work_lock);
    if (!sbi->work_queued) {
        delay = msecs_to_jiffies(dirty_writeback_interval * 10);
        queue_delayed_work(system_long_wq, &sbi->mdb_work, delay);
        sbi->work_queued = 1;
    }
    spin_unlock(&sbi->work_lock);
}

/*
 * hfs_statfs()
 *
 * This is the statfs() entry in the super_operations structure for
 * HFS filesystems.  The purpose is to return various data about the
 * filesystem.
 *
 * changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
 */
static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    struct super_block *sb = dentry->d_sb;
    u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

    buf->f_type = HFS_SUPER_MAGIC;
    buf->f_bsize = sb->s_blocksize;
    buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
    buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
    buf->f_bavail = buf->f_bfree;
    buf->f_files = HFS_SB(sb)->fs_ablocks;
    buf->f_ffree = HFS_SB(sb)->free_ablocks;
    buf->f_fsid.val[0] = (u32)id;
    buf->f_fsid.val[1] = (u32)(id >> 32);
    buf->f_namelen = HFS_NAMELEN;

    return 0;
}

static int hfs_remount(struct super_block *sb, int *flags, char *data)
{
    *flags |= MS_NODIRATIME;
    if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
        return 0;
    if (!(*flags & MS_RDONLY)) {
        if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
            printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
                   "running fsck.hfs is recommended.  leaving read-only.\n");
            sb->s_flags |= MS_RDONLY;
            *flags |= MS_RDONLY;
        } else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
            printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
            sb->s_flags |= MS_RDONLY;
            *flags |= MS_RDONLY;
        }
    }
    return 0;
}

static int hfs_show_options(struct seq_file *seq, struct dentry *root)
{
    struct hfs_sb_info *sbi = HFS_SB(root->d_sb);

    if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
        seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
    if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
        seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
    seq_printf(seq, ",uid=%u,gid=%u",
            from_kuid_munged(&init_user_ns, sbi->s_uid),
            from_kgid_munged(&init_user_ns, sbi->s_gid));
    if (sbi->s_file_umask != 0133)
        seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
    if (sbi->s_dir_umask != 0022)
        seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
    if (sbi->part >= 0)
        seq_printf(seq, ",part=%u", sbi->part);
    if (sbi->session >= 0)
        seq_printf(seq, ",session=%u", sbi->session);
    if (sbi->nls_disk)
        seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
    if (sbi->nls_io)
        seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
    if (sbi->s_quiet)
        seq_printf(seq, ",quiet");
    return 0;
}

static struct inode *hfs_alloc_inode(struct super_block *sb)
{
    struct hfs_inode_info *i;

    i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
    return i ? &i->vfs_inode : NULL;
}

static void hfs_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
}

static void hfs_destroy_inode(struct inode *inode)
{
    call_rcu(&inode->i_rcu, hfs_i_callback);
}

static const struct super_operations hfs_super_operations = {
    .alloc_inode    = hfs_alloc_inode,
    .destroy_inode  = hfs_destroy_inode,
    .write_inode    = hfs_write_inode,
    .evict_inode    = hfs_evict_inode,
    .put_super  = hfs_put_super,
    .sync_fs    = hfs_sync_fs,
    .statfs     = hfs_statfs,
    .remount_fs     = hfs_remount,
    .show_options   = hfs_show_options,
};

enum {
    opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
    opt_part, opt_session, opt_type, opt_creator, opt_quiet,
    opt_codepage, opt_iocharset,
    opt_err
};

static const match_table_t tokens = {
    { opt_uid, "uid=%u" },
    { opt_gid, "gid=%u" },
    { opt_umask, "umask=%o" },
    { opt_file_umask, "file_umask=%o" },
    { opt_dir_umask, "dir_umask=%o" },
    { opt_part, "part=%u" },
    { opt_session, "session=%u" },
    { opt_type, "type=%s" },
    { opt_creator, "creator=%s" },
    { opt_quiet, "quiet" },
    { opt_codepage, "codepage=%s" },
    { opt_iocharset, "iocharset=%s" },
    { opt_err, NULL }
};

static inline int match_fourchar(substring_t *arg, u32 *result)
{
    if (arg->to - arg->from != 4)
        return -EINVAL;
    memcpy(result, arg->from, 4);
    return 0;
}

/*
 * parse_options()
 *
 * adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
 * This function is called by hfs_read_super() to parse the mount options.
 */
static int parse_options(char *options, struct hfs_sb_info *hsb)
{
    char *p;
    substring_t args[MAX_OPT_ARGS];
    int tmp, token;

    /* initialize the sb with defaults */
    hsb->s_uid = current_uid();
    hsb->s_gid = current_gid();
    hsb->s_file_umask = 0133;
    hsb->s_dir_umask = 0022;
    hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
    hsb->s_quiet = 0;
    hsb->part = -1;
    hsb->session = -1;

    if (!options)
        return 1;

    while ((p = strsep(&options, ",")) != NULL) {
        if (!*p)
            continue;

        token = match_token(p, tokens, args);
        switch (token) {
        case opt_uid:
            if (match_int(&args[0], &tmp)) {
                printk(KERN_ERR "hfs: uid requires an argument\n");
                return 0;
            }
            hsb->s_uid = make_kuid(current_user_ns(), (uid_t)tmp);
            if (!uid_valid(hsb->s_uid)) {
                printk(KERN_ERR "hfs: invalid uid %d\n", tmp);
                return 0;
            }
            break;
        case opt_gid:
            if (match_int(&args[0], &tmp)) {
                printk(KERN_ERR "hfs: gid requires an argument\n");
                return 0;
            }
            hsb->s_gid = make_kgid(current_user_ns(), (gid_t)tmp);
            if (!gid_valid(hsb->s_gid)) {
                printk(KERN_ERR "hfs: invalid gid %d\n", tmp);
                return 0;
            }
            break;
        case opt_umask:
            if (match_octal(&args[0], &tmp)) {
                printk(KERN_ERR "hfs: umask requires a value\n");
                return 0;
            }
            hsb->s_file_umask = (umode_t)tmp;
            hsb->s_dir_umask = (umode_t)tmp;
            break;
        case opt_file_umask:
            if (match_octal(&args[0], &tmp)) {
                printk(KERN_ERR "hfs: file_umask requires a value\n");
                return 0;
            }
            hsb->s_file_umask = (umode_t)tmp;
            break;
        case opt_dir_umask:
            if (match_octal(&args[0], &tmp)) {
                printk(KERN_ERR "hfs: dir_umask requires a value\n");
                return 0;
            }
            hsb->s_dir_umask = (umode_t)tmp;
            break;
        case opt_part:
            if (match_int(&args[0], &hsb->part)) {
                printk(KERN_ERR "hfs: part requires an argument\n");
                return 0;
            }
            break;
        case opt_session:
            if (match_int(&args[0], &hsb->session)) {
                printk(KERN_ERR "hfs: session requires an argument\n");
                return 0;
            }
            break;
        case opt_type:
            if (match_fourchar(&args[0], &hsb->s_type)) {
                printk(KERN_ERR "hfs: type requires a 4 character value\n");
                return 0;
            }
            break;
        case opt_creator:
            if (match_fourchar(&args[0], &hsb->s_creator)) {
                printk(KERN_ERR "hfs: creator requires a 4 character value\n");
                return 0;
            }
            break;
        case opt_quiet:
            hsb->s_quiet = 1;
            break;
        case opt_codepage:
            if (hsb->nls_disk) {
                printk(KERN_ERR "hfs: unable to change codepage\n");
                return 0;
            }
            p = match_strdup(&args[0]);
            if (p)
                hsb->nls_disk = load_nls(p);
            if (!hsb->nls_disk) {
                printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
                kfree(p);
                return 0;
            }
            kfree(p);
            break;
        case opt_iocharset:
            if (hsb->nls_io) {
                printk(KERN_ERR "hfs: unable to change iocharset\n");
                return 0;
            }
            p = match_strdup(&args[0]);
            if (p)
                hsb->nls_io = load_nls(p);
            if (!hsb->nls_io) {
                printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
                kfree(p);
                return 0;
            }
            kfree(p);
            break;
        default:
            return 0;
        }
    }

    if (hsb->nls_disk && !hsb->nls_io) {
        hsb->nls_io = load_nls_default();
        if (!hsb->nls_io) {
            printk(KERN_ERR "hfs: unable to load default iocharset\n");
            return 0;
        }
    }
    hsb->s_dir_umask &= 0777;
    hsb->s_file_umask &= 0577;

    return 1;
}

/*
 * hfs_read_super()
 *
 * This is the function that is responsible for mounting an HFS
 * filesystem.  It performs all the tasks necessary to get enough data
 * from the disk to read the root inode.  This includes parsing the
 * mount options, dealing with Macintosh partitions, reading the
 * superblock and the allocation bitmap blocks, calling
 * hfs_btree_init() to get the necessary data about the extents and
 * catalog B-trees and, finally, reading the root inode into memory.
 */
static int hfs_fill_super(struct super_block *sb, void *data, int silent)
{
    struct hfs_sb_info *sbi;
    struct hfs_find_data fd;
    hfs_cat_rec rec;
    struct inode *root_inode;
    int res;

    sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
    if (!sbi)
        return -ENOMEM;

    sbi->sb = sb;
    sb->s_fs_info = sbi;
    spin_lock_init(&sbi->work_lock);
    INIT_DELAYED_WORK(&sbi->mdb_work, flush_mdb);

    res = -EINVAL;
    if (!parse_options((char *)data, sbi)) {
        printk(KERN_ERR "hfs: unable to parse mount options.\n");
        goto bail;
    }

    sb->s_op = &hfs_super_operations;
    sb->s_flags |= MS_NODIRATIME;
    mutex_init(&sbi->bitmap_lock);

    res = hfs_mdb_get(sb);
    if (res) {
        if (!silent)
            printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
                hfs_mdb_name(sb));
        res = -EINVAL;
        goto bail;
    }

    /* try to get the root inode */
    hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
    res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
    if (!res) {
        if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
            res =  -EIO;
            goto bail;
        }
        hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
    }
    if (res) {
        hfs_find_exit(&fd);
        goto bail_no_root;
    }
    res = -EINVAL;
    root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
    hfs_find_exit(&fd);
    if (!root_inode)
        goto bail_no_root;

    sb->s_d_op = &hfs_dentry_operations;
    res = -ENOMEM;
    sb->s_root = d_make_root(root_inode);
    if (!sb->s_root)
        goto bail_no_root;

    /* everything's okay */
    return 0;

bail_no_root:
    printk(KERN_ERR "hfs: get root inode failed.\n");
bail:
    hfs_mdb_put(sb);
    return res;
}

static struct dentry *hfs_mount(struct file_system_type *fs_type,
              int flags, const char *dev_name, void *data)
{
    return mount_bdev(fs_type, flags, dev_name, data, hfs_fill_super);
}

static struct file_system_type hfs_fs_type = {
    .owner      = THIS_MODULE,
    .name       = "hfs",
    .mount      = hfs_mount,
    .kill_sb    = kill_block_super,
    .fs_flags   = FS_REQUIRES_DEV,
};

static void hfs_init_once(void *p)
{
    struct hfs_inode_info *i = p;

    inode_init_once(&i->vfs_inode);
}

static int __init init_hfs_fs(void)
{
    int err;

    hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
        sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
        hfs_init_once);
    if (!hfs_inode_cachep)
        return -ENOMEM;
    err = register_filesystem(&hfs_fs_type);
    if (err)
        kmem_cache_destroy(hfs_inode_cachep);
    return err;
}

static void __exit exit_hfs_fs(void)
{
    unregister_filesystem(&hfs_fs_type);

    /*
     * Make sure all delayed rcu free inodes are flushed before we
     * destroy cache.
     */
    rcu_barrier();
    kmem_cache_destroy(hfs_inode_cachep);
}

module_init(init_hfs_fs)
module_exit(exit_hfs_fs)